1. www.argans.co.uk SMOS L2 Ocean Salinity Reprocessed constant calibration L1c OTT drift study 13 April 2011 ARGANS & L2OS ESL ascendingdescending

2. www.argans.co.uk SMOS L2 Ocean Salinity L1c reprocessed constant calibration data: pre-select South Pacific half-orbits: > 2000 grid points in region latitude -30 to 0, longitude -130 to -120 select one half orbit at 6 day intervals: January - December 2010 sub-set ascending (58) & descending (58) orbits OTT1 made using L2OS v500 candidate & compareTBs v1.3, latitude -50 to +10 snaps filtered for: far from land, sun/galactic glint, tec gradient > 20 +0.5 K drift = -1 psu Reprocessed constant calibration L1c OTT

3. www.argans.co.uk SMOS L2 Ocean Salinity

4. www.argans.co.uk SMOS L2 Ocean Salinity L2OS galactic model error: -1K in HH Drift: -0.5 K pa in HH & VV, ascending orbits

5. www.argans.co.uk SMOS L2 Ocean Salinity

6. www.argans.co.uk SMOS L2 Ocean Salinity L2OS galactic model error: +1K in HH & VV Drift: +0.5 K pa in HH & VV, descending orbits

7. www.argans.co.uk SMOS L2 Ocean Salinity Drift -0.5 K pa in HH & VV, same as AFFOV But HH bias now higher then VV (opposite to AFFOV), & unexplained low VV January – end March

8. www.argans.co.uk SMOS L2 Ocean Salinity Drift +0.5 K pa in HH & VV, same as AFFOV But HH bias now higher then VV (opposite to AFFOV), & unexplained low HH & VV January – end March

9. www.argans.co.uk SMOS L2 Ocean Salinity OTT anomaly 20101104T020829 reversed HH & VV bias – why?

10. www.argans.co.uk SMOS L2 Ocean Salinity Cross-pol OTT drifts different from HH & VV in AF & EAF ascendingdescending

11. www.argans.co.uk SMOS L2 Ocean Salinity ascendingdescending Descending OTTs show sun alias moving along AFFOV/EAFFOV hexagon

12. www.argans.co.uk SMOS L2 Ocean Salinity OTT2 from L1BOTT1 from L1C OTTs from L1B (Joe) & L1C (ARGANS) visual match orbit 20101110T013458_20101110T022859 XX/HH YY/VV

13. www.argans.co.uk SMOS L2 Ocean Salinity Conclusions – reprocessed constant calibration data allows identification of long-term drift ESL recommendation for 2011 reprocessing – long-term drift: -0.5 K pa in HH & VV, ascending orbits +0.5 K pa in HH & VV, descending orbits – cross-pol noise/errors? – sun aliases in EAFOV? – L2OS work correct galactic model error ±1 K why short-term OTT irregularities? refine OTT generation procedures

14. www.argans.co.uk SMOS L2 Ocean Salinity Extra slides follow, showing – short integration time OTTs close to long – median OTTs different from mean – impact on OTT quality from too few snapshots

15. www.argans.co.uk SMOS L2 Ocean Salinity AFFOV OTTs from FP short integration time close to long

16. www.argans.co.uk SMOS L2 Ocean Salinity AFFOV OTTs from FP short integration time close to long

17. www.argans.co.uk SMOS L2 Ocean Salinity EAFFOV OTTs from FP short integration time close to long

18. www.argans.co.uk SMOS L2 Ocean Salinity EAFFOV OTTs from FP short integration time close to long

19. www.argans.co.uk SMOS L2 Ocean Salinity median AFFOV OTTs different from mean

20. www.argans.co.uk SMOS L2 Ocean Salinity median AFFOV OTTs different from mean

21. www.argans.co.uk SMOS L2 Ocean Salinity median EAFFOV OTTs different from mean

22. www.argans.co.uk SMOS L2 Ocean Salinity median EAFFOV OTTs different from mean

23. www.argans.co.uk SMOS L2 Ocean Salinity tec gradient filter > 5tec gradient filter > 20 TEC filter reduces number of snapshots: 21 snapshots (left), 210 (right)